In wireless communication systems, fading occurs according to location of a terminal or obstacles. Due to such fading, channel conditions vary in wireless communication systems. In order to improve overall system performance, resources are efficiently allocated to terminals in consideration of their channel quality indications when performing scheduling for the terminals.
For example, a wireless communication system selects a proper Modulation and Coding Scheme (hereinafter, referred to as “MCS”) level according to information on Channel Quality Indication (CQI) reported by a terminal after receiving a signal from a base station. For example, a low MCS level is selected for a terminal in a bad channel condition. Due to the selected low MCS level, a data transfer rate may be reduced. However, reliable transmission is guaranteed and efficient data transmission is enabled.
In a wireless communication system, resources are largely divided into frequency resources and time resources. Optimal allocation of the resources is very important to improve the performance of the wireless communication system.
FIG. 1 illustrates an example of resource allocation in an Orthogonal Frequency Division Multiplexing (OFDM) system. More specifically, FIG. 1 illustrates the allocation of frequency resources and time resources to users in a grid-like fashion.
There is a need for a method for maximizing overall network performance by minimizing inter-cell interference and increasing a resource reuse rate through common resource management between cells in a wireless communication system.
In order to maximize overall network performance, as illustrated in FIG. 2, a resource reuse method is performed in inner regions of cells for reusing the same resource. A coordinated scheduling method is performed in boundary regions of cells for using different resources.
In case of such coordinated scheduling performed in the boundary regions of the cells, the channel quality of terminals may change abruptly when the terminals travel between the inner regions and boundary regions of the cells. However, such abrupt changes are not considered to allocate MCS levels. Accordingly, efficient data transmission is not guaranteed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.